1. Field of the Invention
The present invention relates to a semiconductor element and more particularly, to a CMOS image sensor and a method for fabricating the same.
2. Discussion of the Related Art
A CMOS image sensor is a type of image sensor having a unit pixel manufactured using a CMOS technique. Peripheral circuits in a CMOS image sensor may include a control circuit and a signal processing circuit.
A method for fabricating a CMOS image sensor may employ a salicide process to lower resistance at an active region and at a gate on a pixel region. Metal films used to carry out the salicide process typically have high reflexibility of light, and are formed on the active region except for a photo diode. Particularly, a salicide film may be formed on an edge region of a semiconductor substrate in addition to the pixel region.
The salicide film formed on the edge region of the semiconductor substrate has a low adhesive strength with an insulating film, and thus may cause generation of insulating film particles, such as circle defects, in a subsequent planarization process of the insulating film. If the particles fall down on contact holes a defect, such as a void, may result when contact plugs are subsequently formed.